Washing machine appliances generally include a cabinet which receives a wash tub for containing water or wash fluid (e.g., water and detergent, bleach, or other wash additives). The wash tub may be suspended within the cabinet by a suspension system to allow some movement relative to the cabinet during operation. A basket is rotatably mounted within the wash tub and defines a wash chamber for receipt of articles for washing. During normal operation of such washing machine appliances, the wash fluid is directed into the wash tub and onto articles within the wash chamber of the basket. A drive assembly is coupled to the wash tub and configured to rotate the wash basket within the wash tub to agitate articles within the wash chamber, to wring wash fluid from articles within the wash chamber, etc.
A significant concern during operation of washing machine appliances is the balance of the tub during operation. For example, articles and water loaded within a basket may not be equally weighted about a central axis of the basket and tub. Accordingly, when the basket rotates, in particular during a spin cycle, the imbalance in clothing weight may cause the basket to be out-of-balance within the tub, such that the axis of rotation does not align with the cylindrical axis of the basket or tub. Such out-of-balance issues can cause the basket to contact the tub during rotation and can further cause movement of the tub within the cabinet. Significant movement of the tub can, in turn, generate increased noise and vibrations and/or cause excessive wear and premature failure of appliance components.
Various methods are known for monitoring load balances and preventing out-of-balance scenarios within washing machine appliances. Such monitoring and prevention may be especially important, for instance, during the high-speed rotation of the wash basket, e.g., during a spin cycle. For example, conventional systems monitor motor current or rotational velocity to determine when articles within the tub are in a suitable position for a spin cycle. Alternatively, one or more balancing rings may be attached to the rotating basket to provide a rotating annular mass that minimizes the effects of imbalances. However, such systems often fail to accurately determine the position of articles within the tub or basket or detect an out-of-balance condition. Moreover, such systems often require additional components and/or sensors, thereby increasing the cost and complexity of the appliance.
Accordingly, improved methods and apparatuses for monitoring load balance in washing machine appliances are desired. In particular, methods and apparatuses that provide for accurate detection of a balanced state or compensation for an imbalanced state during a washing operation would be advantageous.